title: ¹¹¹Indium-labeled ultrafine carbon particles; a novel aerosol for pulmonary deposition and retention studies.
abstract: Continuous environmental or occupational exposure to airborne particulate pollution is believed to be a major hazard for human health. A technique to characterize their deposition and clearance from the lungs is fundamental to understand the underlying mechanisms behind their negative health effects. In this work, we describe a method for production and follow up of ultrafine carbon particles labeled with radioactive ¹¹¹Indium (¹¹¹In). The physicochemical and biological properties of the aerosol are described in terms of particle size and concentration, agglomeration rate, chemical bonding stability, and human lung deposition and retention. Preliminary in vivo data from a healthy human pilot exposure and 1-week follow up of the aerosol is presented. More than 98% of the generated aerosol was labeled with Indium and with particle sizes log normally distributed around 79  nm count median diameter. The aerosol showed good generation reproducibility and chemical stability, about 5% leaching 7 days after generation. During human inhalation, the particles were deposited in the alveolar space, with no central airways involvement. Seven days after exposure, the cumulative activity retention was 95.3%. Activity leaching tests from blood and urine samples confirmed that the observed clearance was explained by unbound activity, suggesting that there was no significant elimination of ultrafine particles. Compared to previously presented methods based on Technegas, ¹¹¹In-labelled ultrafine carbon particles allow for extended follow-up assessments of particulate pollution retention in healthy and diseased lungs.
authors.affiliation: Department of Nuclear Medicine, Karolinska University Hospital, Stockholm, Sweden. alejandro.sanchez-crespo@karolinska.se
authors.forename: Alejandro
authors.initials: A
authors.lastname: Sanchez-Crespo
authors.forename: Anna
authors.initials: A
authors.lastname: Klepczynska-Nyström
authors.forename: Anders
authors.initials: A
authors.lastname: Lundin
authors.forename: Britt Marie
authors.initials: BM
authors.lastname: Larsson
authors.forename: Magnus
authors.initials: M
authors.lastname: Svartengren
mesh_terms: D000336:Aerosols; D055598:Chemical Phenomena; D005260:Female; D006108:Graphite / Q000032:analysis / Q000737:chemistry / Q000493:pharmacokinetics* / Q000633:toxicity; D006801:Humans; D007205:Indium Radioisotopes / Q000032:analysis* / Q000097:blood / Q000652:urine; D007553:Isotope Labeling; D008168:Lung / Q000737:chemistry / Q000000981:diagnostic imaging / Q000187:drug effects / Q000378:metabolism*; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D016011:Normal Distribution; D010316:Particle Size; D052638:Particulate Matter / Q000493:pharmacokinetics* / Q000633:toxicity; D010865:Pilot Projects; D011857:Radiographic Image Interpretation, Computer-Assisted; D011877:Radionuclide Imaging; D015203:Reproducibility of Results; D013670:Sodium Pertechnetate Tc 99m / Q000032:analysis / Q000493:pharmacokinetics; D012995:Solubility; D014018:Tissue Distribution; D018675:Toxicity Tests / Q000379:methods*
chemical_list: D000336:Aerosols; D007205:Indium Radioisotopes; D052638:Particulate Matter; C056708:Technegas; D006108:Graphite; D013670:Sodium Pertechnetate Tc 99m